Phytoplankton diversity of a de-mineralized subtropical reservoir of Meghalaya state, northeast India

Abstract

This study monitors the spa-tio-temporal variations of phytoplankton of a soft-water and de-mineralized reservoir of Meghalaya state of northeast India. Phyto-plankton assemblages of the littoral and limnetic regions reveal total 36 species and diverse desmids, and con-tribute dominantly to net plankton abundance. Our results record the quantita-tive importance of Charo-phyta > Bacillariophyta > Dinophyta and Charophyta > Dinophyta, and the ‘spe-cialist’ nature of 11 and six species at the littoral and limnetic regions, respective-ly. Staurastrum spp. and Cosmarium spp. are notable taxa. Phytoplankton indi-cates moderate species di-versity and depicts domi-nance and evenness varia-tions. The individual abiotic factors exert differential in-fluence on various taxa at the two regions and the ca-nonical correspondence analysis registers 73.02 and 71.14% cumulative influ-ence of 10 abiotic factors on the littoral and limnetic as-semblages, respectively. The spatial differences of phytoplankton composition, richness, abundance, im-portant groups and taxa, specialist species, diversity indices and the influence of individual abiotic factors are hypothesised to habitat heterogeneity amongst the sampled regions. This study records notable temporal differences of phytoplank-ton richness, abundance, di-versity and the role of abiot-ic factors vis-a-vis the lim-ited survey of November 1990–October 1991.